Steam boiler



July 21, 19360 T. B. STILLMAN STEAM BOILER Original Filed June 30, 19332 Sheets-Sheet l v INVENTOR uhomas J3. Stillman B ATTORNEY July 21,1936. T. B. STILLMAN STEAM BOILER Original Filed June 30, 1933 2Sheets-Sheet 2 INVENTOR (Lhomas ,B. Stillman B I I- ATTORNEY PatentedJuly 21, 1936 STEAM BOILER Thomas B. Stillman, South Orange, N. J., as-

signor to The Babcock & Wilcox Company, Newark, N. 3., a corporation ofNew Jersey Application June 30, 1933, Serial No. 678,344 Renewed January23, 1936 10 Claims. (01. 12%336) My present invention relates to theconstruction and operation of water tube boilers in which the boilersteam generating surface is mainly concentrated ina single vertical bankof tubes extending between a lower water drum and an upper steam andwater drum receiving heating gases from an integral fluid cooled furnacelaterally adjoining 1e tube bank. Boilers of this type have beenrecently developed for industrial plants having low head room andrelatively small steam generating requirements.

The object of my present invention is an improved construction of atwo-drum boiler of the type described which is characterized by anarrangement of fuel burning provisions and a furv nace constructionpermitting the eflicient burning of a fiuid fuel in suspension atextremely high rates of heat release per unit of furnace volume,

' a superheater location and arrangement providing a high degree ofsuperheat and a compact arrangement of the superheater tubes,facilitating an accurate control of the degree of superheat, andpermitting easy access to the superheater for tube replacement andcleaning, simple and efiective means for regulating the superheattemperature, and a more effective arrangement of the hot and coldheating surfaces in the furnace chamber.

The various features of novelty which characterize my invention arepointed out with particularity in the claims annexed to and formin apart of this specification. For a better understanding of the invention,its operating advan-' tages and specific objects attained by its use,reference should be had to the accompanying drawings and descriptivematter in which I have illustrated and described a preferred embodimentof my invention.

Of the drawings:

Fig. l is a sectional elevation of a steam boiler embodying myinvention, taken on the line Il of Fig. 2 with a portion of the tubebank cut away to show superheater;

Fig. 2 is a horizontal section taken on the line 2-2 of Fig. l; p

Figs. 3 and 4 are horizontal sections taken on the lines 3-3 and 4-4respectively, of Fig. 1; and

Fig. 5 is a vertical section taken on the line 55 of Fig. 1.

The steam boiler illustrated in the drawings has a horizontally arrangedlower water or mud drum Ill supported in a cradle H and connected to andsupporting a similarly arranged upper steam and water drum l2 by anupright bank of tubes l3, extending between and symmetrically arrangedrelative to the drums I and I 2. The major portions of the tubes l3 arestraight and parallel, and the ends of the tubes are bent to enter thedrums l0 and I2 radially. The axes of the drums are in verticalalignment and the 0 tubes l3 are arranged in staggered rows extendinglongitudinally of the drums. The drums and tube bank are positioned in ahousing having vertical front and rear refractory walls 14 and Irespectively, and side walls l6 and I1 at opposite 10 sides of the tubebank I3, the wall l6 being inclined upwardly from the tube bank and thewall I! being laterally spaced a considerable distance from the oppositeside of the tube bank.

The housing space between the tube bank I3 and the side wall I! andclosed at its ends by the walls Hi and I5 is the boiler furnace orcombustion chamber l8, coextensive with the tube bank IS. The two rowsof tubes [3a nearest the furnace chamber are of larger diameter and morewidely spaced than the remaining rows of tubes l3 in the bank. The outerside wall I! of the furnace is formed by a row of substantially straightstud tubes 19 with the inter-tube spaces closed by refractory material20. In the upper part of the wall ll, the refractory material extendsover the inner face of the wall, while in the lower part of the wall theinner faces of the tubes l9 are ex-' posed to the radiant heat of thefurnace chamber. as shown in Figs. 1, 3, and 4. The lower ends of thetubes l9 are connected to a horizontally arranged header 2| resting in acradle 22. The center of the header 2| is at substantially the samelevel as that of the drum l0 and the drum and header are connected belowthe connections of the outermost row of tubes [3a by a row of horizontalspaced tubes 23. The spaces between the tubes 23 are closed byrefractory blocks 24 resting on the tubes, the upper surfaces of whichform a smooth floor for the furnace chamber. The floor and sidewallsdescribed are backed by suitable insulating material 25 and metal plates26 forming the boiler outer casing. The boiler furnace is supported byI-beams 21 and 28 extending below the floor and header 2| respectively.

The upper ends of the tubes l9 are connected to a horizontally arrangedheader 30 having its axis at a slightly lower level than the axis of thedrum l2, and substantially in vertical alignment with the lower header'2 I. The header 30 is connected to the drum l2 by a lower row ofstraight tubes 3|, and an upper row of bent tubes 32, both of which arelongitudinally spaced and open into the drum l 2 above the points ofconnection of the tubes I 3 The spaces between the lower row of tubes'3lare closed by tile pieces 33 so that the tubes 3| define the roof of thefurnace chamber. The upper rows of tubes 32 are also backed by heatinsulating material 25 andplates 2B. 'The furnace chamber so formed isthus surrounded on all sides along its length by rows of cooling tubes.

The fluid cooled furnace of the character de- I scribed is especiallyintended for burning of a fluid fuel in suspension at extremely highrates of heat release per unit of furnace volume and with high boilerefficiencies. The provisions for supplying fuel to the furnace aremounted in the front wall l4 and consist of a battery of eight fuel oilburners 36 having fuel burner ports 31 symmetrically arranged In twovertical rows relative to the side walls of the furnace chamber. Inoperation, the fuel burners discharge parallel streams of fuelhorizontally into the furnace chamber towards the rear or target wallthereof. Air for combustion is supplied through a casing 38 extendingalong the front wall and surrounding the burner ports. The several flameand gas streams starting rearwardly, turn in the furnace chamber andthen flow transversely of the tube space in intimate contact with thetubes therein, while maintaining a horizontal direction, withoutbaflling and therefore with a minimum draft loss.

The Water tubes in a number of rows transversely of the tube bank l3 andextending from the front wall l4 about half the length of the tube bankare omitted to provide a. space for a steam superheater having verticalinlet and outlet headers 40 and 4| respectively, and an intermediateheader 42, arranged side-by-side along the front wall of the boiler. Theinlet headers are connected to the intermediate header 42 by groups oflooper tubes 43 and 44 respectively, arranged horizontally and extendinglongitudinally of the tube space within the confines of the tubes bankl3. The innermost rows of tubes l3 and lill adja cent the combustionchamber are left in position to provide a water screen for protectingthe superheater. The described superheater location results in anunusually compact boiler and accessible superheater. The horizontalarrangement of the superheater tubes between rows of vertical watertubes provides a gas mixing action which minimizes Stratification 'ofthe heating gases.

At the outer sideof the tube bank l3 the wall I6 is arranged to form' anupwardly expanding gas duct 45, in the upper end of which is positionedan air heater formed by a bank of tubes 46, extending across the duct45, as shown in Fig. 5. Above the air heater tubes 45, the duct 45 isprogressively tapered and connected to a stack outlet A desirablecontrol of the superheat temperature is efiected by dividing the tubespace and duct 45 into two parallel gas passes 45 and 45" by a. verticalbaflle plate 45 extending between the drums l0 and I2 adjacent thelargest looped superheater tube 43, as shown in Fig. 2. The plate 45extends to the rear wall l6 and upwardly to the top of the tubular airheater. At the upper end of the plate a rod 48 is rotatably mounted andserves-as the support for a control damper 49. As shown in Figs. 1 and5, the damper. is movable between the full and dotted line positions toregulate the gas flow through the passes 45 and 45 and thereby controlthe amount of gases passing over the superheater tubes 43 and 44. Theflue and damper dimensions are so proportioned that in the extremepositions of the damper, a limited gas flow will exist through the passover which the damper is arranged. Thedamper may be manually orautomatically operated through a wheel 50 and chain 5|.

Complete absence of baflies causing gases to change direction is animportant feature of my construction, which contributes toward minimumdraft loss, a factor of importance in high capacity light weightboilers. Another feature of importance is the end firing which allows alonger flame travel than is possible with cross firing without excessivewidth of boiler and makes most effective use of the furnace volume.

Certain novel structural features disclosed but not claimed herein aredisclosed and claimed. in my copending application Serial No. 678,343,filed June 30, 1933.-

While in accordance with the provisions of the statutes I haveillustrated and described herein the best forms of my invention nowknown to me, those skilled in the art will understand that changes maybe made in. the form of the apparatus disclosed without departing fromthe spirit of the invention covered by my claims, and that certainfeatures of my invention may sometimes be used to advantage without acorresponding usev of other features.

I claim:

1. A steam boiler having an upper steam and water drum, a lower waterdrum, a substantially vertical bank of steam generating tubes extendingbetween and connected to said drum along the length thereof, meansforming a fluid cooled furnace chamberlaterally adjoining the spacecontainingv said tube bank and communicating therewith substantiallythroughout its length, said means including a row of radiant heatedtubes having their opposite ends connected to said drums and definingthe outer side wall of said furnace chamber, a group of verticallyspaced fuel burners for burning fuel in suspension in said furnacechamber positioned in an end wall of said furnace chamber and effectinga substanthe tubes therein, a heating gas outlet adjacent said steam andwater drum at the side of said tube bank O posite said furnace chamber,vertically arranged superheater headers adjacent the firing end of saidboiler, looped superheater tubes connecting said headers and extendinglongitudinally of said tubespace and terminating substantially midway ofthe length of and within said tube bank, and a vertical baiileseparating the space containing said superheater tubes from theremaining portion of said tube space.

2. A steam boiler having an upper steam and water drum, a lower waterdrum, a substantially vertical bank of steamgenerating tubes extend ingbetween and connected to said drum along the length thereof, meansforming a furnace chamber laterally adjoining the space containing saidtube bank and communicating therewith substantially throughout itslength, a fuel burner positioned in an end wall of said furnace chamberfor burning fuel in suspension in said furnace chamber and effecting asubstantially horizontal flow of heating gases longitudinally throughsaid furnace chamber and then transversely of said tube space andcontacting with the tubes therein, a heating gas outlet at the side ofsaid tube said tube space, and a damper operable to control the portionof the heating gases contacting with said superheater tubes.

3. A steam boiler having an upper steam and water drum, a lower waterdrum, a substantially vertical bank of steam generating tubes extendingbetween and connected to said drum along the length thereof, meansforming a furnace chamber laterally adjoining the space containing saidtube bank and communicating therewith substantially throughout itslength, means for burning fuel in suspension in said furnace chamber andeffecting a substantially horizontal flow of heating gases transverselyof said tube space and contacting with the tubestherein, a heating gasoutlet at the side of said tube bank opposite said furnace chamber, agroup of superheater tubes extending part of the length of said tubespace and within said tube bank, a vertical bafile adjacent the end ofthe space containing said superheater tubes, and a. damper in saidheating gas outlet operable to control the portion of the heating gasescontacting with said superheater tubes.

4. A steam boiler having an upper steam and water drum, a lower waterdrum, a vertically disposed bank of steam generating tubes extendingbetween and connected to said drums along the length thereof, meansforming a furnace chamber laterally adjoining the space containing saidtube bank and opening thereto substantially throughout the height andlength of said tube bank, means for introducing and burning fuel insuspension in said furnace chamber and generating heating gases flowinglongitudinally in said furnace chamber and transversely of said tubespace in contact with the tubes therein, a heating gas outlet from saidtube space at the side of said tube bank opposite said furnace chamber,a group of superheater tubes positioned within said tube bank andoccupying only a portion of the heating gas flow area through said tubespace, and damper means arranged and operable to vary the ratio betweenthe portion of the heating gases passing through said tube spacein'contact with said superheater tubes and the portion of the heatinggases passing through said tube space in contact with only steamgenerating tubes.

- 5. A two-drum steam boiler having an upper steam and water drum, alower water drum, a vertically disposed bank of steam generating tubesextending between and connected to said drums along the length thereof,means forming a fluid cooled furnace chamber laterally adjoining thespace containing said tube bank and opening thereto substantiallythroughout the height and length of said tube space, said meansincluding a row of water tubes laterally spaced from said tube bank andhaving their upper ends connected to said upper drum, a header connectedto the lower ends of said water tubes, a second row of water tubesconnecting said heater to said lower drum, means for introducing andburning fuel in suspension in said furnace chamber and generatingheating gases flowing longitudinally in said furnace chamber andtransversely of said tube space in contact with the tubes therein, aheating gas outlet from said tube space at the side of said tube bankopposite said furnace chamber, a group of superheater tubes positionedwithin said tube bank and occupying only a portion of the heating gasflow area through said tube space, and damper means arranged to vary theratio between the portion of the heating gases passing through said tubespace in contact with said superheater tubes and the portion of theheating gases passing through said tube space in contact only with steamgenerating tubes.

6. A two-drum steam boiler having side and end walls forming a setting,a pair of substantially parallel horizontally disposed upper and lowerdrums in said setting, a vertically disposed bank of water tubesextending between and connected to said drums along the length thereofand disposed at both sides of the plane including the longitudinal axesof said drums, a group of steam superheater tubes positioned within saidtube bank and occupying only a portion of the heating gas flow areatherethrough, a furnace chamber laterally adjoining said tube bank andarranged substantially wholly at one side of said axial plane andopening substantially throughout its length to the space containing saidtube bank, a-row of water tubes extending along the side of the furnacechamber opposite said tube bank and having their upper ends connected tosaid upper drum and their lower ends to said lower drum, a fuel burnerdischarging through a wall of said furnace chamber for burning fuel insuspension therein and generating heating gases flowing transversely ofsaid tube bank, a heating gas outlet at the opposite side of said tubebank, and damper means arranged and operable to vary the ratio betweenthe portion of the heating gases passing through said tube space incontact with said superheater tubes and the portion of the heating gasespassing through said tube space in contact with only steam generatingtubes.

7. A two-drum steam boiler having side and end walls forming a setting,a pair of substantially parallel horizontally disposed upper and lowerdrums in said setting, a vertically disposed bank of water tubesextending between and connected to said drums along the length thereofand disposed at both sides of the plane including the longitudinal axesof said drums, a group of steam superheater tubes positioned within saidtube bank, a furnace chamber laterally adjoining said tube bank andarranged substantially wholly at one side of said axial plane andopening substantially throughout its length to the space containing saidtube bank, a row of water tubes extending along the side of .the furnacechamber opposite said tube bank and having their upper ends connected tosaid upper drum, a header extending longitudinally of said furnacechamber and connected to the lower ends of said wall tubes, a row ofwater tubes connecting said header to said lower drum, means closing thespaces between and covering said last named tubes to define the fioor ofsaid furnace-chamber, a fuel burner discharging through an end wall ofsaid furnace chamber for burning fuel in suspension therein andgenerating heating gases flowing longitudinally in said furnace chamberand transversely of said tube bank, and a heating gas outlet at theopposite side of said tube bank.

8. A two-drum steam boiler having side and end walls forming a setting,a pair of substantially parallel horizontally disposed upper and lowerdrums in said setting, a vertically disposed bank of water tubesextending between and connected to said drums along the length thereofand disposed at both sides of the plane including the longitudinal axesof said drums. a group of steam superheater tubes positioned within saidtube occupied by the upper end portions of the tubesin said tube bank, arow of water tubes extending along the side of the furnace chamberopposite said tube bank and having their upper ends connected to saidupper drum, a header extending longitudinally of said furnace chamberand connected to the lower ends of said wall tubes, a row of water tubesconnecting said header to said lower drum, means defining a floor' forsaid fur.- nace chamber, a fuel burner discharging through a verticalwall of said furnace chamber for burning fuel in suspension therein andgenerating heating gases flowing horizontally in said furnace chamberand transversely of said tube bank, and a heating gas outlet at theopposite side of said tube bank. t

9. A two-drum steam boiler having side and end walls forming a setting,a pair of substantially parallel horizontally disposed upper and lowerdrums in said setting, a vertically disposed bank of water tubesextending between and connected to said drums along the length thereofand disposed at both sides of the plane including the longitudinal axesof said drums, a group of steam superheater tubes positioned within saidube bank, a furnace chamber laterally adjoin ing saidtube bank andarranged substantially wholly at one side of said axial plane andopening to the space containing said tube bank substantially throughoutthe length and height of at least the portion thereof containing saidsuperheater tubes, said tube bank including a. plurality of rows ofwater tubes at the furnace side of said superheater tubes with the tubesin the row nearest the furnace chamber being of larger diameter than thewater tubes at the opposite side of said superheater tubes, a row ofwater tubes extending along the side of the furnace chamber oppositesaid tube bank and hav ing their upper ends connected to said upper drumand theirlower ends to said lower drum, means defining a floor for saidfurnace chamber, a fuel burner for burning fuel in suspension in saidfurnace chamber and generating heating gases flowing horizontally insaid furnace chamber and transversely of said tube bank, and a heatinggas outlet at the opposite side of said tube bank.

10. A two-drum steam boiler having side and end walls forming a setting,a pair of substantially parallel horizontally disposed upper and lowerdrums in said setting, a vertically disposed bank of water tubesextending between and connected to said drums along the length thereofand disposed at both sides of the plane including the longitudinal axesof said drums, a group of steam superheater tubes positioned within andextending longitudinally of said tube bank, a furnace chamber laterallyadjoining said tube bank and arranged substantially wholly at one; sideof said axial plane and opening substantially throughout its length tothe space containing said tube bank, a row of water tubes extendingalong the side of the furnace chamber opposite said tube bank and havingtheir upper ends connected to said upper drum, aheader extendinglongitudinally of said furnace chamber and connected to the lower endsof said wall tubes, a row of water tubes connecting said headerto saidlower drurn, means closing the spaces between and covering said lastnamed tubes to define a flat floor of substantial area for said furnacechamber, a fuel burner discharging through an end wall of said furnacechamber for burning fuel in suspension therein and generating heatinggases flowing longitudinally in said furnace chamber and transversely ofsaid tube bank, a

heating gas outlet passage at theopposite side of said tube bank, and abank of air heating tubes arranged in said outlet passage adjacent saidupper drum.

THOMAS B. STILLMAN.

